[CMake] Add `project` in `runtime/CMakeList.txt`

[aoli]

Summary

• project is required when runtime/CMakeList.txt is the top-level CMakeList.txt file. This will establish version and policy settings.

[aoli]

Add stage2 dependencies.

[aoli]

Remove -Wl,-z,defs.

[aoli]

ping..

[srhines]

runtimes/CMakeLists.txt

444

Is this dependency needed now? I assume runtimes depends on runtimes-configure, but maybe I am mistaken.

[aoli]

Remove dependency. Update comments.

[pirama]

Chris, can you look at this change? This can help simplify the build setup for the Clang used in Android.

[beanz]

runtimes/CMakeLists.txt

444

Uh... This part of the patch should be done differently.

This hack is in place because of how clang finds c++ headers relative to itself, so we need to configure the runtimes directory (which copies the c++ headers) otherwise we can't actually build anything with the stage1 compiler.

Making clang-bootstrap-deps depend on the runtimes target should be done separately only if the next stage build is intending to link against runtime libraries from the stage1 build, and even then I'm not sure we should be depending on the runtimes target, I'd much rather the dependency was setup on the top-level target for the runtime library (i.e. libcxx, libunwind, compiler-rt...).

[aoli]

runtimes/CMakeLists.txt

444

I agree.

Shall we bring some new variables like LLVM_USE_STAGE1_LIBCXX, LLVM_USE_STAGE1_LIBUNWIND ...?

[beanz]

runtimes/CMakeLists.txt

444

Configuring the bootstrap builds is currently done in Clang, not LLVM. We probably want an option like BOOTSTRAP_USE_<libname> which we can interpret in <clang>/CMakeLists.txt where we handle the other bootstrap options.

We don't want the option to name a specific stage because we do support many-layered bootstraps.

[aoli]

Revert adding dependencies.

[aoli]

runtimes/CMakeLists.txt

444

I reverted this change and I'll bring a new patch to add bootstrap options.

[aoli]

runtimes/CMakeLists.txt

444

By using BOOTSTRAP_USE_<libname>, it will also pass USE_<libname> as variables to stage2 because the variables start with BOOTSTRAP_. To avoid passing unused variables, shall we use CLANG_BOOTSTRAP_USE_<libname> or something better?

[beanz]

runtimes/CMakeLists.txt

444

Good call. CLANG_BOOTSTRAP_... is a good way to go.

[beanz]

LGTM.

[aoli]

Remove redundant logic.

runtimes/CMakeLists.txt

 # triggered by the external project call for the runtimes target below.
 if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
 
   function(runtime_register_component name)
     set_property(GLOBAL APPEND PROPERTY SUB_COMPONENTS ${name})
   endfunction()
 
   cmake_minimum_required(VERSION 3.4.3)
+  project(Runtimes C CXX ASM)
 
   # Add the root project's CMake modules, and the LLVM build's modules to the
   # CMake module path.
   list(INSERT CMAKE_MODULE_PATH 0
     "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
     "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/modules"
     "${LLVM_LIBRARY_DIR}/cmake/llvm"
   )
if(runtimes)
     endif()
 
     # TODO: This is a hack needed because the libcxx headers are copied into the
     # build directory during configuration. Without that step the clang in the
     # build directory cannot find the C++ headers in certain configurations.
     # I need to build a mechanism for runtime projects to provide CMake code
     # that executes at LLVM configuration time to handle this case.
     if(NOT LLVM_BUILD_INSTRUMENTED AND CLANG_ENABLE_BOOTSTRAP)
       add_dependencies(clang-bootstrap-deps runtimes-configure)
     endif()
 
     if(LLVM_INCLUDE_TESTS)
       set_property(GLOBAL APPEND PROPERTY LLVM_ADDITIONAL_TEST_DEPENDS runtimes-test-depends)
       set_property(GLOBAL APPEND PROPERTY LLVM_ADDITIONAL_TEST_TARGETS check-runtimes)
 
       set(RUNTIMES_TEST_DEPENDS
           FileCheck